Fluid impregnated electric cable



July 25, 1950 c. E. BENNETT FLUID IMPREGNATED ELECTRIC CABLE Ftiled Aug.29, 1945 Water a Moistureproof Sealing Agent Vornished Gloss InventorCHARLES E.BENNETT DJ J. M

flltorney Patented July 25, 1950 25 16347 FLUID HHPREGNATED ELECTRICCABLE Charles E. Bennett, Ridgewood, N. J., assignor-to' Thekonite-Callender Cable Company, Incorporated, Paterson, N

Jersey a. corporation of New Application August 29, 1945, Serial No.613,257

line filled with insulating fluid maintained under superatmosphericpressure.

It is customary under present practice to insulate these conductors atthe factory, impreg-- hate them with insulating fluid, and then toencase each conductor in a temporary lead sheath to retain theimpregnant and to prevent the entry of moisture to the insulation intransit and while installing. This sheath adds materially to the cablecost to the customer, in time, labor and material; the sheath addsconsiderably to the weight of the cable thus increasing shipping costs;and finally the sheath has to be removed at the installation siteinvolving more expense.

The present invention provides a construction wherein the temporary leadsheath is dispensed with entirely, and the expense incident to its useeliminated.

2 Claims. (Cl. 17425) In the accompanying drawings, I have illus- Itrated two embodiments of my invention.

Fig. l is a cross section through a sealed cable system of the typewherein several individually insulated conductors are enclosed in a pipeline containing insulating fluid under superatmospheric pressure.

Fig. 2 is a fragmentary part sectional elevational view of one of theconductors of the cable system of Fig. 1; and

Fig. 3 is a view similar to Fig. 2 of another embodiment of myinvention.

Referring to the drawings in detail, and first of all to Figs. 1 and 2:

2 designates the individually insulated conductors of a sealed cablesystem wherein these conductors are enclosed in a pipe line 4 filledwith insulating fluid maintained under superatmospheric pressure or theorder of two hundred pounds per square inch.

Each conductor 2 is insulated with paper tape 6 which in accordance withconventional practice is wound hellcally about the conductor, layer uponlayer until the desired wall thickness has been built up.

About the paper insulation 6 I wrap a moistureand waterproof tape 8 ofaluminum or other metal foil, or a tape of paper treated to render itmoistureand waterproof. This tape is wound hellcall with a substantialoverlap, and covered with a waterand moistureproof sealing agent such aspolybutene sold commercially under the name of Vistas. The tape itselfbeing moistureand waterproof and sealed with Vistag, it will be apparentthat no moisture or water can pass through the sheath thus provided, andthat the fluid insulation with which the conductor insulation isimpregnated before leaving the factory cannot escape.

In installing this type of cable long lengths are drawn into the pipeline 4. It is necessary that the cable be protected against damage inthis operation.

Accordingly I wrap heavy canvas tape it about the impervious sheath justdescribed. The carevas tape ID is wrapped helically and is inter calatedwith metal shielding tape 12. The shielding tape is imperforate.

As a further protection against damage and to facilitate drawing in ofthe cable I wrap metal armor wire it about the cable exterior. Thisarmor is D-shaped in cross section, with its fiat side in contact withthe cable, and wound with a long pitch in the opposite hand to the wrapsbeneath it.

It will be apparent from the foregoing that my invention provides acable construction wherein the cable conductor is finished at thefactory, that is insulated and impregnated, and may be shipped andinstalled without danger of loss of the fluid insulation, without injurybecause of moisture or water, and without the necessity of removing thetemporary lead sheath heretofore found necessary to protect the cable.Obviously this is a considerable advance over conventional practice.

In the construction illustrated in Fig. 3, I have provided a somewhatsimpler construction than the one Just described but with all of theadvantages thereof. J

In this embodiment of my invention I employ insulating paper tape 8 asbefore, and immediately about this insulation I wrap imperforateshielding metal tape l6, copper, for example, intercalated withvarnished glass tape l8. A coating of a sealing agent such, for example,as the Vistag above referred to, is applied over these tapes so asthoroughly to seal the same against the entry of water or moisture.

As in the embodiment of my invention first described, D-armor I4 isapplied to the cable exterior, being-wound in the opposite hand to theintercalated tapes l8 and I8.

It will be appreciated that in both embodiments of my invention thenecessity for a temporary lead or other sheath, with the expenseincident thereto, is eliminated, yet the cable is at all times fullyprotected against loss of the cable impregnant and .against thedeleterious efiects of the elements.

It is to be understood that changes may be made in the details ofconstruction and arrange ment of parts hereinabove described within thepurview of my invention.

What-I claim is: 1

1. A high tension cable installation comprising in combination aconductor, a wall of porous insulation around the conductor, animperforate fiexlblesheath of waterand moisture proof material wrappedhelically about the said insulation, a permanent water andmoisture-proof sealing coating for said sheath, intercalated tapes ofmetal and fabric wound helically over said coating, a solid metal stripwrapped in an open helix about the last mentioned tapes, a body of fluidinsulating material filling the porous insulation and all spaces beneaththe said sealing coating, 9. fluid-tight pipe enclosing the .cable, theinternal diameter of the pipe being large enough relative to the overalldimensions of the cable to permit the cable to be drawn into the pipe,and a body of fluid ,under superatmospheric pressure filling the spacebetween the sheathed cable and the wall of the pipe.

2. A high tension cable installation comprising in combination aconductor, a wallof porous insulation around the conductor, animperforate' flexible sheath of water-and moisture-proof materialwrapped helically about the said insulation,

a permanent water and moisture-proof sealing coating for said sheath, ametal shielding tape intercalated with a fabric tape. wound helically'over said coating, 9. solid metal strip wrapped in an open helix aboutthe last mentioned tapes, a body of fluid insulating material .fillingthe porous insulation and all spaces beneath the said sealing coating, afluid-tight pipe enclosing the cable, theinternal diameter of. the pipebeing large enough relative to the overall dimension of the cable topermit the cable to be drawn into .7 thepipe, and a body of fluid undersuperatmospheric pressure filling the space between the sheathed cableand the wall of the pipe.

CHARLES E. BENNETT.

' REFERENCES CITED The following references are of record in the file ofthis patent:

England Jan. 26, 1937

